Kernel-memory disclosure via unlocked KDSETMODE write
Published Feb 16, 2022 · Updated Aug 3, 2024
Out-of-bounds read in Linux Kernel 5.15-rc1 allows local users to disclose kernel memory by racing virtual-terminal ioctls. The KDSETMODE path in drivers/tty/vt/vt_ioctl.c writes vc_mode without the console lock, allowing concurrent console operations to derive an out-of-range vc_visible_origin. Exploitation requires control of the relevant terminal or CAP_SYS_TTY_CONFIG and winning a multithreaded race; the reported consequence is confidentiality loss only.
Summary
What happened
Out-of-bounds read in Linux Kernel 5.15-rc1 allows local users to disclose kernel memory by racing virtual-terminal ioctls. The KDSETMODE path in drivers/tty/vt/vt_ioctl.c writes vc_mode without the console lock, allowing concurrent console operations to derive an out-of-range vc_visible_origin. Exploitation requires control of the relevant terminal or CAP_SYS_TTY_CONFIG and winning a multithreaded race; the reported consequence is confidentiality loss only.
The record
- CVE
- CVE-2021-3753
- Published
- Feb 16, 2022
- Updated
- Aug 3, 2024
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-362, CWE-125, T1005
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Feb 16, 2022CVE publishedPublication date reported by the CVE source.
- Aug 3, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=Linux kernel 5.15-rc1
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- KDSETMODE virtual-console race trigger sequenceproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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